Actually I wouldn't consider that a sampling detector because there are no caps on the individual outputs to actually sample and hold the signal ... it's more akin to a ring diode detector only using CMOS transistors instead of diodes .... wshat makes Dan's cirsuit truly unique is not that he uses a digital switch circuit but that he uses a sample and hold circuit for demodulating and RF signal ... if we are going to get picky about it the credit should go to the inventor of the sample and hold circuit which has been used in digital audio for almost 3 decades
Go read Dan Tayloe's presentation on the Norcal QRP website and see how he uses the 'sampling' caps to restrict the bandwidth **immeadiately** after the detector (actually the caps are an intregal part of the detector) which greatly increases the blocking dynamic range and two tone dynamic range by filtering out close-in interfering signals you find during contests and pile ups ... and at an extremely low current use that none of the tradition high performance circuits even come close to ... the traditional 2N5109 feedback amplifier used after a ring diode mixer/detector alone often uses more current than the entire radio Dan designed John --- In [email protected], "Chris Hirt" <[EMAIL PROTECTED]> wrote: > > Hi all > Look at soft_radio/Files/HDR2005/QSD_OLDY.PDF and You see another > history of Quadrature Sampling Detector. > I found the old Wireless World article last week and I think its > interesting for all hardware frontend workers of a SDR. > > Chris > ------------------------ Yahoo! Groups Sponsor --------------------~--> Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/ELTolB/TM --------------------------------------------------------------------~-> Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/soft_radio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
